During his sentencing Tuesday, the prosecution said that Knysz threatened corrections officers by shaping his hands like a gun.

Knysz denied those allegations in court.

Knysz was sentenced to life in prison without the possibility of parole for Butterfield’s killing. He shot the Trooper in the head Sept. 9, 2013 during a traffic stop in Mason County before being arrested along with his wife Sarah in Manistee County.

Butterfield, 43, died later that night during surgery.

Knysz was also found guilty of vehicle theft, carrying a concealed weapon, felony firearm and being an habitual offender.

Jennifer Sielski, Butterfield’s fiancee, spoke at Knysz’s sentencing. She talked about a message she sent Paul the day he was killed, telling him she loved him.

“To this day the message remains unread on his cellphone,” she said.

“Your honor, I know that nothing can bring Paul back into this world or ease the pain of my devastating loss,” Sielski said. “But just as Paul did his duty to uphold the law, serving his community to keep us all safe, I ask that you do the same by holding the responsible parties accountable for their heartless actions, which caused the death of my beloved fiancé. I felt like the luckiest woman in the world just to be a part of Paul’s life. He had the ability to make me laugh when I was feeling my worst. He could inspire me when I felt defeated. He was trustworthy when I needed a friend. He was comforting when I needed to share my feelings. He was intuitive when I had a problem I tried to hide, and he protected me when I needed to feel safe. He was my friend, my inspiration, my hero, my soulmate.”

Butterfield’s father also had a lot to say to the man who took his son’s life and compared Knysz’s lack of accomplishments by the age of 19 to what his son had done by that age.

“At the age of 19 years old you have effectively ended the life of freedom for yourself,” Butterfield’s father said. “At 19, Paul was a high school graduate, a state class A cross-country champion and enrolled at the University of Tennessee for track and country. He ran marathons world-wide and participated in several triathalons…what have you accomplished by the age of 19? You’ve certainly made a name for yourself in law enforcement but not in the same way our son did.”

But Butterfield’s father wasn’t finished there.

“Paul was 43 years old when you murdered him,” he said. “By the time Paul was 43 years old, he served proudly in the U.S. Army where he ran and was in charge of the 23rd infantry division running team. He then entered the Michigan State Police where he proudly served for 14 honorable years.”I do not know if you’re planning on giving a statement to the court but if you say how sorry you are for what happened it’ll be for one reason and one reason only and as that is you got caught.”

Knysz did decide to speak out in court by saying, “First, I’d like to say I’m sorry for the pain and suffering that I caused the family and friends of trooper Butterfield. I’d like to also apologize to my family for everything I’ve done and the pain I’ve put them through.”

Then,while looking at trooper Butterfield’s family Knysz said, “I’m sorry, I never meant to take the life of your son. I never meant for any of this to happen.”

He continued to say, “Last I’d like to point out that my wife and my mother had no voluntary participation in this heinous crime.”

Sarah Knysz testified against her husband as part of a plea agreement. She is currently serving two to five years for being an accessory after the fact and vehicle theft